The proposed research is concerned with studying, through perceptual asymmetry, surgical, and memory procedures: The verbal (language) and spatial processing lateralities of the brain; the possible lateral specializations of the hemispheres for emotional cue-processing and for control of vocalization; the type (general or serial) of short-term memory impairment characteristic of chronic dyslexics and whether it extends to spatial rather than just verbal materials; and the most promising perceptual tasks for revealing differential hemispheric efficiencies for spatial functions. The groups studied will be left-handed persons differing in familial sinistrality and sex, normal right-handers, congenitally deaf persons, dyslexic persons, and domestic guinea pigs. Results of these experiments should clarify our understanding of the cerebral lateralization of various processes and should provide data relevant to the development of innocuous diagnostic procedures for measuring the relative lateralities of such processes in man.